Those TSG adjusters sit on nominally 3sp shift cables, but on a folder everything can be tricky. One of the 3 speeds is squeezed into 2 speed space with 10- and 11-speed hardware and is very finicky to set up. Yet these TSG adjusters work better than the brand names I mentioned all of which were specifically meant for the shift cables.
My basic understanding of inline adjusters is that the good ones have threads etc that don't move over time, better build quality and tighter threading between the two moving parts, that hold their position properly. I guess these ones are well made.
If they work well, great.